Improve Memory Efficiency of process_results() Override

[peterallenwebb]

Is this your first time submitting a feature request?

• I have read the expectations for open source contributors
• I have searched the existing issues, and I could not find an existing issue for this feature
• I am requesting a straightforward extension of existing dbt-snowflake functionality, rather than a Big Idea better suited to a discussion

Describe the feature

The current implementation of dbt-snowflake's process_results() override holds a full additional copy of query results in memory. For queries with large result sets, such as those used by get_catalog(), this can limit dbt's ability to operate in memory-constrained environments.